I agree, these numbers look like an indication of very developed athlete, with AeT close to AnT and all the zones “compressed” to the top of the range. And then it totally makes sense that with narrowing of the zones you need so precise 8 bpm interval.
Just to provide context I think its fair to reference the source of the text to provide context etc. The OP has extracted text from this post (Iñigo San Millán training model - #1026 by BTSeven7 - Training - TrainerRoad) on the TrainerRoad forum which is part of the a long standing thread discussing the ISM training model (Iñigo San Millán training model - Training - TrainerRoad)
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A thing I normally do when training that zone is talking sentences to my self to see if I’m in the zone 
“I’m really, really, really, good” and in that “good” I need to breath in again or I die
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Sorry, you’re right, let me put it in!
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Guys,
Inigo is pretty clear saying that Z2 is the range where the FatMáx occurs. But where starts Z4 and Z5? The Long intervals he prescribes, like zone 4, starts when Fat oxidation is 0?
"You can make relatively quick changes in your glycolytic efficiency. You can take an untrained person with a vo2 max of 20 and you could take them to 30 in a period of months with the right amount of training. A 50% improvement in a few months. It’s very difficult to see a 50% improvement in mitochondrial function in a few months. It speaks to why this level of training should be thought of in the same way that you think of accumulating wealth: which is it’s day-in and day-out small compounded gains over years and years. "- Peter Attia
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I am new here, but have spend quite some time reading lots of fantastic stuff, on this great forum. Thank you so much to all of you for the insightfull and inspiring contributions. I try now to maybe give something back to those of you, who still like to use, and discuss/learn heart rate (zones). Inigo San Millan etc…, maybe this could be of a little value.
Thank you very much for the paper(table 18.2) 
.
Im struggling a bit with the Heart rate zone 2 and 4 also though. I know it is just an example and not generic/applicable in general. But, I dont have access to prober testing, and I am an old school heart rate guy so…
The power zones, in the table, are almost classic (Coggan/Inscyd)
Zones in %FTP (264watts)
z1, (AR) < 56,8
z2: (E) 57 - 75,8
z3: (T) 76 - 92.8
z4: (LT) 93 - 1.08
z5/6 (V/An) 1.08+
I find the heart rate zones (HR)from table 18.2, a little strange though.
The matching heart rate zones for 2,3 and 4 based on LTHR:145, are in this case
z2: 82-88% (119-128) (not 103-125)
z3 89-93% and (129-135)
z4 94-100 % (136-145) accordingly
If he/she wants to train the turbo (glycolytic) it is best done around 97%LTHR or higher!
In this case, when talking heart rate, zone 4 starts 9 heart beats under LTHR (wich is close to Neal Henderson, Sufferfest/Systm) and his definition of sub-LT
In some cases using google I have seen Inigos Zones 2-4 being like this:
zone / %Lthr/ (beats from lthr)
z2: 85 - 91 (Minus 15 to minus 25 beats of Lthr) , target 88%lthr
z3: 91.5 - 96 (minus 6 to minus 14)
z4: 97-100 (lthr minus 5 to lthr)
**z5+: 101+ (lthr+1 and above)
In conclusion from this table, and those three tables I have found:
If you are a trained cyclist using heart rate as a guidance. you could go on like this.
An athlete should never stop training in zone 2, with a target of 85 - 88 % LTHR, or 75 %FTP and a range of 85-92%of lthr. This falls in line with “Olympiatoppen”, Norway, and British cycling) who labels everything below 82 % off HRmax low intensity. Maybe it also falls in line with Seilers new 2-zone-model around Lt1. We will wait and see.
I am sorry for the length, and poor editing. Im more confused than when I started (All I know is that I know nothing, and soforth)
Even this for pro is too high for what they do!
You are more than welcome in this post and thanks for sharing your thoughts, it’s always a pleasure to discuss training!
Thanks Xavier. And yes it seems high, but Inigo zone 2 also seems a bit higher than ex. coggan zone 2. More like low/mid tempo a la Steve Neal or something. I have tried it out this year and it works in the winter, but when I have to train the hard sessions more frequently (x2 week) i always fall back to easier rides than Inigo prescripts. At least I think.
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The challenge for the pro is that their LT1 and LT2 are only about 8 bpm apart. Hence why they have to be careful going over LT1 as it may take them over LT2 very easily. With most amateurs having a gap of 20-30 bpm between LT1 and LT2 they can afford to be a little over LT1 without worrying about going over their LT2. Most amateurs don’t work on raising their LT1 , hence the large gap.
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If you watch McNulty trainings on Strava you see that most of the zone 2 rides are probably between 230-300 watts with HR beeing low, like 130 bpm. I saw in a training 184 bpm, but he probably can reach 200. As you see, zone 2 is quite high in power but the HR still low. Maybe we’re doing wrong in pushing the HR up, don’t know
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I don’t think so Phil. It’s kinda individual. For some is just 10 bpm, for others 20…
I know a very good world tour with 155 VT1 and 175 VT2
The zones might look high but that’s because his athletes are well trained, metabolically efficient and genetically gifted. Iñigo set’s his athlete’s zone 2 around < 1.5 mmol/L, often under 1 mmol/L. Power zones are based on lactate levels and %VO2max.
Yup.
Which World Tour pro are you referring to?
He’s been most vocal these past years about Pogačar, and rightly so. But check out these resources:
• #201 - Deep dive back into Zone 2 | Iñigo San-Millán, Ph.D. (Pt. 2) - Peter Attia
• Assessment of Metabolic Flexibility by Means of Measuring Blood Lactate, Fat, and Carbohydrate Oxidation Responses to Exercise in Professional Endurance Athletes and Less-Fit Individuals - PubMed
• Netter’s Sports Medicine, Ch. 18, Jonh C. Hill, Inigo San Millan
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Can’t tell but he is one of the 10 best GC contenders
He won the 2020 and 2021 Tour de France, winning three different jerseys during each Tour.